1. Field of the Invention
The present invention relates to an image input apparatus, an image output apparatus, and a data transfer method for transferring data between an image input apparatus and an image output apparatus, and more particularly, to data transfer between an image input apparatus and an image output apparatus when printing an input image sensed with an image input apparatus typified by a digital camera or a video camera using an image output apparatus typified by a printer.
2. Description of the Related Art
Recently, digital cameras (image input apparatuses) that can sense an image with a simple operation and convert the sensed image into digital image data have come to be widely used. When printing out an image sensed with such a camera and using it as a photograph, ordinarily, it is common to do something like the following: First, the sensed digital image data is sent from the digital camera to a PC (computer). Then, after the image data is processed at the PC, the processed image data is output from the PC to a color printer and printed.
In addition, a color printing system capable of transferring digital image data directly from the digital camera to the color printer without going through a PC and printing an image has also been developed. Hereinafter, such a printing system is referred to as “direct printing”. In such a direct color printing system, for matching colors, a technique called color management system (CMS) that matches color reproduction between different image devices is used. CMS is comprised of a device profile that describes the color reproduction characteristics of each image device and a color matching method that carries out color matching.
As one example of a technology that implements this type of color management, a system that carries out color management based on an ICC color profile defined by the International Color Consortium (ICC) is known. This CMS first defines a device-independent hub color space or a profile connection space (PCS) for carrying out color matching, and then implements color management using a source profile that defines color conversion from a device color space to the hub color space/PCS and a destination profile that defines color conversion from the hub color space/PCS to the device color space.
The CMS processing system is composed mainly of two conversion processes. First, based on the source profile, color signal values in the device color space suited to an input side device of an input image are converted into color signal values in the hub color space/PCS. Then, based on the destination profile, the color signal values in the hub color space/PCS are converted into color signals in the device color space suited to an output side device.
In relation to CMS, the following types of technologies have also been implemented. First, using a framework for file specification such as TIFF (Tag Image File Format) file or PDF (Portable Document Format) file, a profile is imbedded in the file. Then, the PC or device carries out color conversion based on the imbedded profile.
At the same time, an EXIF (Exchangeable Image File Format) specification is known. In the EXIF specification, information relating to characteristics of the sensed image and to image sensing conditions is imbedded in each image file, which enables the output device to determine the characteristics of the image during image sensing and the settings used during image sensing for each image file.
Under conditions such as these, there is a desire to make a tint of the output image a color that reflects individual preferences. In this regard, a method that makes it possible to obtain the tint or tone characteristics that a user desires in a printing system for printing a color image has been proposed (for example, JP-2000-190572-A).
In addition, a printing apparatus capable of switching among a plurality of color correction systems (for example, JP-H07-298077-A) and a method for confirming color processing results by displaying on a display unit of the device the results of implementing a plurality of device profiles (for example, JP-H11-017970-A) have also been proposed.
However, to output an image of a color that the user prefers using a simple method that does not go through a PC entails the following problems.
First, in the method for imbedding the device profile as typified by the ICC profile in the image profile, because the device profile must be imbedded in each image file, the size of the image files increases, lengthening the data transfer time as a result. In a device such as a digital camera, which is widely used as an image input device, ordinarily a battery is used as the device's power supply. With the transfer time directly affecting battery life, even a slight reduction in transfer time is desired.
Moreover, with the method of storing the parameters used during image sensing as typified by EXIF, because the user must estimate the image sensing parameters that will produce the desired result during image sensing, the user must estimate the image to be obtained from the settings of the camera, which requires a high degree of skill.
In addition, with the method for reflecting user preferences of JP-2000-190572-A, a method in which the user specifies the desired color from among basic colors is disclosed. However, if the user is not knowledgeable about or does not have experience with color processing, changing such typical colors as red, blue, green, and yellow to give a photograph one has taken oneself the desired tint is a difficult thing to do.
Further, with the printing apparatus capable of switching among a plurality of color correction methods described in JP-H07-298077-A, it is necessary to store the device profile of the input device in the output device. As a result, the color correction method cannot be freely set for all input devices, which limits the user's choices.
Moreover, the method for confirming color processing results by displaying on the display unit of the device the results of implementing a plurality of device profiles described in JP-H11-017970-A has the following defect. Namely, with the display unit mounted on the device such as the digital camera that is widely used as the image input device, the display area is very small and difficult to see clearly, and satisfactory confirmation cannot be made.